LNA QUIETS MOBILE SATCOM RECEIVERS

RECEIVER designers often consider the low-noise amplifier (LNA) to be a ''no-compromise'' component due to its influence on sensitivity. It is the receiver's first active component after the antenna, heavily im pacting the overall noise figure. But the LNA also has significant eff ect on the receiver's dynamic range, making it one of the most import- ant single components in a receiver. Due to its influence, an LNA usua lly is associated with high cost. Fortunately, a low-cost, high-volume solution has recently been developed by Watkins-Johnson Co. (Milpitas , CA) for low-earth-orbit (LEO) satellite handsets. The plastic-packag ed LNA features a noise temperature of 60 K (equivalent to a noise fig ure of 0.8 dB) at 2.5 GHz while also achieving 25-dB gain, uncondition al stability, and wide dynamic range.